* Introduced base TestFixture class for testing design of custom exceptions: CustomExceptionDesignGuidelinesTestFixture ** Refactored all ExceptionTest classes to used this new base-class. * Functional testcoverage for Core.Components.DotSpatial\Layer\BruTile\Configurations * PersistentCacheConfiguration no longer supports SQLite cache * ITileSourceFactory now guarantees that all ITileSource elements returned have a WmtsTileSchema. * TODO: More functional coverage for WmtsLayerConfiguration Related to Issue [WTI-1088]